As new airplanes are being developed, it is becoming more of a challenge to enable the pilot to see outside the airplane during critical phases of flight. For example, some conventional supersonic transport airplanes, such as the Concorde, have a system for lowering the nose during landing approach to allow the pilots to see the approach and runway environment during this phase of the flight. If the nose were not lowered, the airplane's long nose in front of the pilot and the fact that the airplane is at a high angle of attack during landing, would prevent the pilots from looking over the nose and seeing the runway.
Furthermore, it is believed that some future airplanes will employ what is known as "synthetic vision". One form of synthetic vision may be a digital display which is provided to the pilots to represent the external environment under selected weather conditions. The digital display could involve a flight deck display screen interfaced with a digital data base. Any images provided to the screen would originate in the data base. Aircraft sensor data might be overlayed as data base imagery or some component of the sensor data could be conditioned and blended with data base imagery. Thus synthetic vision as well as other future vision systems might allow removal of the cockpit/flight deck forward windows in order to reduce weight and eliminate the cockpit/flight deck external skin bulge thereby reducing drag.
In certain aircraft it may be desirable not to have a nose which must be lowered to allow the pilot's to see the landing environment. In addition, it may be desirable to provide a method of allowing the pilots to directly see the runway during approach and landing without having to rely solely on a form of artificial vision.
A number of conventional devices for looking out of an aircraft have been disclosed. For example, U.S. Pat. No. 1,045,152 by Kelsey discloses an airplane having a window in the bottom of the fuselage to allow the pilot to see out the bottom of the airplane. In addition, U.S. Pat. Nos. 4,264,044 and 4,160,534 by White, and assigned to the assignee of the present invention, disclose an operating station for an airplane refueling boom which includes a window for permitting a boom operator to view the boom.